Compound projectile



June 26, 1956 G. E. FROST COMPOUND PROJECTILE Filed March 5, 1952JNVENTOR. George E. P m-5% BY deelzuw AGENT This invention relatesgenerally to ammunition and i more particularly to compound projectilesand to a method for making improved projectiles of this type.

Ammunition projectiles areordinarily composed of a metal core and aharder metal jacket. These projectiles are usually referred to ascompound projectiles and have replaced most of the lead slugs formerlyutilized as pronited States atetlt jectiles because of the relativelypoor accuracyof the soft lead slug due to excessive deformation of thesurface thereof by the rifiing in the gun barrel. The soft metal core ofcompound projectiles is protected from this deformation by the hardermetal jacket which substantially completely encloses those portionsadjacent the barrel rifiing. In this type of projectile, the nose or tipof the bullet is formed from the core metal and the jacket is normallyreferred to as a base jacket. In still another type of compoundprojectile, a second jacket often called a tip jacket is utilized inconjunction with the base jacket to completely enclose the softer core.

Since the advent. of the compound projectile, it has been recognizedthat the effectiveness thereof is impaired if the base jacket and coreseparate when the projectile strikes the target. When the jacketseparates from the core upon impact with the objective, there is a lossin penetrating power and destructive action. Consequently, many methodsfor securing or locking the core to the base jacket have been proposed.One of the earlier suggestions is disclosed in U. S. Patent 680,549,issued to Smith August 13, 1901. Smith perforated the jacket wallcovering the base or rear end of the core and drove or otherwise forcedthe jagged prongs of metal formed in making the perforation into thecore. It was found in practice, however, that the prongs of metal breakand that this type of lock does not prevent separation of the core fromthe jacket when the projectile strikes the target. Probably the mostcommon practice heretofore has been to embed a portion of the jacketwall in the core metal by forming one or more circumferential rings orsimilar indentations therein after the core has been consolidated withinthe jacket. type which are formed after the core and jacket have beenassembled taper to smaller dimensions within the core than adjacent thejacket wall and cannot be forced to a very great depth into the corewithout excessive thinning of the jacket metal. As a result, suchindentations do not securely lock the core and base jacket together andthe core frequently moves relative to the jacket when the target isstruck by the projectile.

it is therefore an object of this invention to provide an improvedcompound projectile. It is another object of this invention to provide anovel lock between the base jacket and core of compound projectiles. Afurther object of this invention is to provide a novel method for makinga compound projectile. A still further object is to provide a projectilehaving the core and jacket thereof securely locked against relativemovement.

Other objects and advantages will become apparent Indentations of this2,751,845 Patented June 26, 1956 2 from the following detail descriptionand accompanying drawing, in which,

Figures l, 2, and 3 are vertical views of base jacket and punchassemblies illustrating successive steps in a process embodying thisinvention, and j Figure 4 is a vertical view partly in section of aprojectile illustrating an embodiment of this invention.

In accordance with this invention, the foregoing ob jects as well asothers are accomplished, generally speak ing, by providing a compoundprojectile having the core secured to the jacket thereof by means of aprotuberance integral with the jacket wall; the protuberance having ashoulder or portion of greater dimension adjacent the end embedded inthecore. It has been, found that the metal slug utilized as the core of acompound projectile can be forced about the periphery of a protuberanceof this type and into a position substantially contiguous with the innersurface of the jacket by means of the conventional pressing operationutilized heretofore to consolidate the core within the jacket. Inaccordance with this invention, the jacket is locked to the core byindenting the jacket wall, shaping the indented metal to form such aknob-like protuberance and then assembling the core and jacket.

Referring now to the drawing for a more detailed description of oneembodiment of this invention, Figure 1 illustrates a conventionalgliding metal base jacket 1 with a cylindrical boss 3 formed in the endthereof. In forming this boss, jacket 1 is inserted in a conventionalcore and jacket assembly die with the end or base thereof resting onpunch 5'. Punch 2 having a cavity 6 in the end thereof is inserted injacket 1 against the inner surface of the jacket wall and punch 4 ismoved upward and the area of the jacket wall between punch 4 and cavity6 of punch 2 is cold worked to form boss 3.

As shown in Figure 2, punches 4 and 5 are retained in the positionsshown in Figure l but punch 2 is withdrawn and a semi-spherical endedpunch 7 is inserted in jacket 1. The wall forming the closed end of boss3 is then compressed between punch 7 and punch 4 which cold work themetal in the unconfined end of boss 3 and force it to flow at rightangles to the direction of the applied pressure to form a flange orshoulder 8 around the periphery of boss 3 and convert it into a roundedprotuberance resembling a knob 11 comprising a flange 8 and acylindrical stem 12.

After the formation of the knob 11 from boss 3 as shown in Figure 2,punch 7 is withdrawn and a lead slug 10 is inserted in jacket 1 andpressed by means of a punch 9 to consolidate it within jacket 1 andabout the periphery of knob 11 as shown in Figure 3. The assembly ofjacket 1 and core 10 are then formed into a compound projectile such asshown in Figure 4 with conventional tools designed to impart the desiredprofile thereto.

Unlike most projectiles of the prior art, the jacket and core of theprojectile of this invention are securely locked and separation thereofupon impact with an objective is prevented by the knob-like protuberance11. The shoulder of the protuberance provides a lock between the coreand jacket which is much stronger than the lock provided by the rathershallow indentations in the jacket wall heretofore utilized in compoundprojectiles. Due to this shoulder embedded in the core, shearing of thecore metal and separation from the jacket is prevented.

While in the foregoing specific embodiment a gilding metal jacket and alead core are assembled to form a projectile, other suitable metals canbe utilized for making these component parts. For instance, soft leadalloys containing minor quantities of antimony or arsenic can beutilized to advantage for the core of some projectiles and the jacketcan be made from various copper base al- 3 I loys,'aluminum or iron.Likewise, instead of forming a cylindrical boss in the first step of theprocess, a polygonal-, triangularor irregular-shaped indentation can beformed in the jacket Walland the knob-like protuberance thus need not berounded. i

In addition to the foregoing suggested modifications in the embodimentdescribed in detail herein, other modifications can be made withoutdeparting from the spirit or scope of this invention. This invention isparticularly useful in the type of projectile illustrated in Figure 4and can be utilized to advantage in making other types of mushroomingand other compound projectiles.

Having thus described this invention what is claimed is:

1. A projectile comprising a core and a jacket, said jacket having amushroom shaped protuberance embedded in said core comprising a stemportion of substantially uniform cross-sectional dimensions throughoutits length and terminating in a closed end having a rim thereabout whichextends outwardly from the walls of the stem into said core.

2. The projectile of claim 1 wherein said core is a lead alloy.

3. The projectile of claim 1 wherein said core is lead and said jacketis a harder metal jacket.

4. The projectile of claim 1 wherein the stem of said protuberance issubstantially cylindrical.

5. In a compound projectile, a protuberance formed in the jacket wallhaving an end'adjacent'the jacket wall, a stem terminating in a closedend of greater cross-sectional dimension having a rim thereaboutembedded in the core of said projectile.

6. A projectile comprising a core and a jacket, said jacket having amushroom shaped protuberance embedded in said core comprising a stemportion of substantially uniform cross-sectional dimensions throughoutits length and terminating in a closed end having a rim thereabout whichextends outwardly from the walls of the stem, said core filling saidjacket and extending around said rim, whereby the core is locked to thejacket.

References Cited in the file of this patent UNITED STATES PATENTS680,550 Smith Aug. 13, 1901 1,059,212 Ross Apr. 15, 1913 1,059,213 RossApr. 15, 1913 1,134,797 Wood Apr. 6, 1915 2,333,091 Crasnofi Nov. 2,1943 FOREIGN PATENTS 583,097 Germany Aug. 28, 1933 527,611 Great BritainOct. 11, 1940

1. A PROJECTILE COMPRISING A CORE AND A JACKET, SAID JACKET HAVING AMUSHROOM SHAPED PROTUBERANCE EMBEDDED IN SAID CORE COMPRISING A STEMPORTION OF SUBSTANTIALLY UNIFORM CROSS-SECTIONAL DIMENSIONS THROUGHOUTITS LENGTH AND TERMINATING IN A CLOSED END HAVING A RIM THEREABOUT WHICHEXTENDS OUTWARDLY FROM THE WALLS OF THE STEM INTO SAID CORE.